A GOA (Gate driver on Array) circuit, or referred to as a scan driving circuit, in a common display device needs to simultaneously provide scan signals of multiple pulse waveforms, for example, each pixel in an AMOLED (Active Matrix/Organic Light Emitting Diode) display device needs to be driven by three scan signals Rn, Gn, En in common (where n represents a stage number or a pixel row number of a shift register unit). While, in order to simultaneously provide scan signals of different pulse waveforms to each row of pixels, a traditional approach uses a different clock signal line to control a different GOA circuit unit respectively, to thereby generate scan signals for each type of pulse waveform in a relatively independent way. But along an increased demand for high resolution and narrow border in the pertained art, as already known by the inventor, width of mutually independent clock signal lines (usually at least two groups of clock signal lines) has greatly affected reduction of wiring area associated.